Thread-braking device for needle threads

ABSTRACT

A brake drum has a row of reversing thread guides by which threads are doubled-up on the peripheral brake surface of the drum to form open loops. When the brake drum is turned, the circumferential lengths of the brake surface portion engaged by the legs of the open loops are varied so that the brake force acting on the threads can be adjusted as required for the operations of needles to which the threads are supplied.

United States Patent inventor Oskar Eigenmann 99 St. Gallerstrasse 9320, Arbon,

Switzerland Appl. No. 838,239

Filed July 1, 1969 Patented Jan. 19, 1971 Priority July 10, 1968 Switzerland N0. Nr.10290/68 THREAD-BRAKING DEVICE FOR NEEDLE THREADS l0 Claiins, 3 Drawing Figs.

0.8. CI 112/254, 242/ l 54 Int. Cl. D051: 47/00 Field of Search 1 12/255,

[56] References Cited UNITED STATES PATENTS 2,746,410 5/1956 Rassons 112/254 3,009,433 11/1961 Kuhn ll2/254X 2,696,608 12/1954 Hangartner l12/255X FOREIGN PATENTS 405,055 7/1966 Switzerland 1 12/241 1,254,660 7/1961 France 1 12/254 1 Primary Examiner-Jordan Franklin Assistant Examiner-George l-l. Krizmanich Attorney-Michael S. Striker ABSTRACT: A brake drum has a row of reversing thread guides by which threads are doubled-up on the peripheral brake surface of the drum to form open loops. When the brake drum is turned, the circumferential lengths of the brake surface portion engaged by the legs of the open loops are varied a so that the brake force acting on the threads can be adjusted as required for the operations of needles to which the threads are supplied.

slssslozs PATENTED JAM 91911 INVENTOR.

THREAD-BRAKINGDEVICE FOR NEEDLE THREADS BACKGROUND OF THE INVENTION the transverse bores is difficult and time consuming.

Another braking device according to the prior art provides an axially extending rod adjacent the peripheral surface of the brake drum, and threads are guided about the rod and have portions engaging the braking surface of the drum. By revolv- .ing the rod about the axis of the drum outwardly of the periphery of the same, the circumferentiallength of the portions of the brake surface of the drum engaged by the threads is varied, so'that the brake force is adjusted.'The apparatus has the disadvantage that the threadingof the threads about the rod is difficult, and that thethreads slide in axial direction along the rod and become entangled.

SUMMARY OF THE INVENTION It is the object of the invention to overcome the disadvantages of known braking devices for threads, and to provide a braking device for this purpose which is easily threaded,

consists of few inexpensive parts, and operatesreliably.

With these objects in view, the present invention provides an angularly adjustable braking device provided with a plurality of reversing thread guides through which open loops of the threads are arethreaded whereby. two thread portions move van axis; at least one, and preferably a plurality of reversing thread guides secured to the periphery of the brake meansi first guide means for supplying a-thread to the reversing thread guide; second guide means for guiding the thread away from the thread guide; and adjusting means for turning the brake means with the reversing thread guide in opposite directions.

The thread guideholds a doubled-up thread forming an open loop having a head portion slidably engaging the reversing thread guide, andfirst and second leg portions enthread to the firstleg portion of the open loop. and move thread away from the second leg portion. When the adjusting means turn the brake means, the circumferential length of the portions of the brake surface engaged by the leg portions of the open loopis varied, so that the brake force acting on the "thread is adjusted.

The adjusting means may be manually operated, but can also be operated under the control of program control means 19A which also control the operations of the needles to which the threads are supplied.

Each reversing thread guide is preferably an'open hook permitting easy insertion of'the thread, and the peripheral surface of the brake drum is advantageously covered' with a plush cover.

The first .and second guide means by-which the thread is ,supplied to and removed from the braking drum, are preferably angularly-staggered about the axis of the brake meansso that the circumferential. lengths of the portions of the brake surface engaged by leg portions of the open loop, are different.

.The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims.

The invention itself however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a fragmentary side elevation illustrating a braking deviceaccording to the invention;

FIG. 2 is a front elevation illustrating the braking device and adjusting means for the same as provided in a two-tier cmbroidery machinerand FIG; 3 is a fragmentary side elevation of the apparatus illustrated in FIG. 2, part of the machine being omitted for the sake of clarity.

Y DESCRIPTION OF THE PREFERRED EMBODIMENTS Two rows of bobbins 1 are provided in each tier of the machine, and as best seen in FIG. 1, two rows of pins or spindles 2 are mounted on a supporting plate 3 and rotatably support bobbins 1 so that threads 6 can be wound off bobbins I. Support plates 3 are secured to supporting frame parts 22 on bothsides of the machine, only one frame part being shown in FIG. 2. First thread guide means 5 are provided which include two rows of guide eyes 5a through which threads 6 are threadedAdjacent each guide eye, a friction cover 20'. which gaging circumferential portions of the peripheral brake surface. The first and second guide means respectively supply may consist of a plush fabric, is provided for increasing the friction of threads 6. Braking drums 8 are mounted in the upper and lower portions of the machine, as shown in FIG. 2,

. and have shaft portions 8a supported for turning movement in frame portions 22. A worm gear 13 or 14 is secured to each shaft portion 8a and meshes with a worm 15 or 16 on a shaft portion 18a or 17. A coupling means 21 permits turning of shaft 18a with worm 15 relative to a shaft 18 which, together with shaft 17, is turned by,an adjusting means 19, which may be a brake motor. By operation of adjusting means 19, brake drums 8 are simultaneously turned.

Only one brake drum 8 is shown in FIG. 1, and it will be understood that the other brake drum is arranged and constructed in the same fashion. Brake drum 8 has a cylindrical hollow body covered by a tubular sleeve 20 consisting of plush fabric. A row of axially spaced reversing thread guides 7 is secured to the upper portion of brake drum 8.

As is best seen in FIG. I, the threads 6 passing through alternating staggered guide eyes 50 pass over a circumferential part-cylindrical portion of the outer peripheral brake surface of cover 20 from a point a to a reversing thread guide 7. The thread is guided through the reversing thread guide and doubled-up with the thread guide from guide means 5 so that between the point a and the respective reversing thread guide, an open loop consisting of a head portionslidably guided by reversing thread guide'7, and two leg portions abutting the outer brake surface of cover 20 is formed. The reversed thread portion is guided over the brake surface to the point b .and then guided over a second guide means 9 which extends along the length of the brake drum 8 to guide all threads-6 toward a pair of rods 23 and 24 mounted on levers l0 and 11.

- From rods 24, threads 6 are guided to the needles of a textile machine, such as an embroidery machine. Due to the operations of the needles, threads 6 are pulled in the direction of the arrowwhile being supplied through guide eyes 5a from bobbins l. The portions-of each thread 6 between point a and the respective reversing thread guide 7, and the portion between thesame and the point b move in opposite directions and encounter friction to an amount depending on the circumeyes 5 and the adjacent friction covers 20 equalizes the tensions of the portions of threads 6 between the braking drum 8 and the bobbins 1.

Assuming that the threads are supplied to the needles of an automatic program controlled embroidery machine, the punched cards by which the needle operations are controlled, also control the operation of the adjusting means 19 which turn the brake drums 8. The brake force exerted by each brake drum 8 depends on its angular position. For example, when brake drum 8 in H0. 1 is turned in counterclockwise direction, the reversing thread guide 7 approaches the point a, and one leg of an open loop formed by a thread 6 is eliminated so that the brake force is reduced. On the other hand, if the brake drum is turned in clockwise direction, reversing thread guide 7 moves to the right, and the length of the open loop and of the corresponding brake surface portion engaged by the same is increased, resulting in a greater braking force.

The adjusting means 19 has manual means so that the adjustment of the brake force of each brake drum 8 can be obtained by manual operation. Such manual adjustment may also be carried out in accordance with the texture and quality of the threads used. When coupling means 21 is loosened, shafts l8 and 180 can be turned relative to each other for obtaining a different relative angular position of the upper and lower brake drums 8. Since the reversing thread guides are open hooks located in planes perpendicular to the axis of brake drum 8, it is very easy to thread each thread 6 through a reversing guide hook 7 to form the open loop consisting of a leg portion extending to point a, a second leg portion extending to point b, and a head portion passing over a portion of the reversing guide hook 7.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of thread braking devices for textile machines differing from the types described above.

While the invention has been illustrated and described as embodied in a thread-braking device having a brake drum with reversing thread guides, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

lclaim:

l. Thread-braking device, comprising, in combination, a brake means having a peripheral brake surface; means mounting said brake means for turning movement about an axis; at least one reversing thread guide secured to the periphery of said brake means and being adapted for holding a doubled-up thread forming an open loop having a head portion slidably engaging said reversing thread guide and first and second leg portions engaging circumferential portions of said peripheral brake surface; first guide means for supplying to said peripheral brake surface a thread forming said first leg portion of said open loop; second guide means for guiding said thread of said second leg portion away from said peripheral brake surface so that said first and second leg portions of said open loop slide in opposite directions on said portions of said brake surface; a and adjusting means for turning said brake means with said reversing thread guide in opposite directions for varying the circumferential lengths of said portions of said brake surface engaged by said first and second leg portions, respectively, whereby the brake force acting on said thread is adjusted.

2. Thread-braking device as claimed in claim 1 wherein a plurality of axially aligned reversing thread guides is secured to said braking surface of said brake means; wherein said first guide means include a plurality of guides for supplying a plurality of threads which are respectively doubled-up on said brake surface by said reversing thread guides; and wherein said second guide means guide said threads away from said peripheral brake surface.

3. Thread-braking device as claimed in claim 1 wherein said brake means includes a brake drum having a peripheral cylindrical brake surface.

4. Thread-braking device as claimed in claim 1 wherein said first and second guide means are disposed angularly spaced from each other about said axis so that the circumferential lengths of said portions of said brake surface engaged by said first and second leg portions, respectively, are different.

5. Thread-braking device as claimed in claim 1 wherein said reversing thread guide is an open hook.

6. Thread-braking device as claimed in claim 1 wherein said reversing thread guide is a hook located in a plane perpendicular to said axis, and being open on one side, and closed on the other side for slidingly engaging said head portion of said open loop.

7. Thread-braking device as claimed in claim 1 wherein a plurality of axially aligned reversing thread guides is secured to said braking surface of said brake means; wherein said first guide means include a plurality of guides for supplying a plurality of threads which are respectively doubled-up on said brake surface by said reversing thread guides; wherein said second guide means guide said threads away from said peripheral brake surface, and are adapted to guide the threads to the needles of a textile machine; comprising program control means for said machine; and wherein said program control means operate said adjusting means in accordance with the operations of said needles.

8. Thread-braking device as claimed in claim 1 including means for manually operating said adjusting means.

9. Thread-braking device as claimed in claim 1 wherein said first guide means include a guide eye for the thread, and a brake surface adjacent said guide eye for frictionally engaging said thread.

10. Thread-braking device as claimed in claim 1 wherein said brake means includes a brake member, and a cover surrounding said brake member, said cover being made of plush fabric and forming said peripheral brake surface. 

1. Thread-braking device, comprising, in combination, a brake means having a peripheral brake surface; means mounting said brake means for turning movement about an axis; at least one reversing thread guide secured to the periphery of said brake means and being adapted for holding a doubled-up thread forming an open loop having a head portion slidably engaging said reversing thread guide and first and second leg portions engaging circumferential portions of said peripheral brake surface; first guide means for supplying to said peripheral brake surface a thread fOrming said first leg portion of said open loop; second guide means for guiding said thread of said second leg portion away from said peripheral brake surface so that said first and second leg portions of said open loop slide in opposite directions on said portions of said brake surface; a and adjusting means for turning said brake means with said reversing thread guide in opposite directions for varying the circumferential lengths of said portions of said brake surface engaged by said first and second leg portions, respectively, whereby the brake force acting on said thread is adjusted.
 2. Thread-braking device as claimed in claim 1 wherein a plurality of axially aligned reversing thread guides is secured to said braking surface of said brake means; wherein said first guide means include a plurality of guides for supplying a plurality of threads which are respectively doubled-up on said brake surface by said reversing thread guides; and wherein said second guide means guide said threads away from said peripheral brake surface.
 3. Thread-braking device as claimed in claim 1 wherein said brake means includes a brake drum having a peripheral cylindrical brake surface.
 4. Thread-braking device as claimed in claim 1 wherein said first and second guide means are disposed angularly spaced from each other about said axis so that the circumferential lengths of said portions of said brake surface engaged by said first and second leg portions, respectively, are different.
 5. Thread-braking device as claimed in claim 1 wherein said reversing thread guide is an open hook.
 6. Thread-braking device as claimed in claim 1 wherein said reversing thread guide is a hook located in a plane perpendicular to said axis, and being open on one side, and closed on the other side for slidingly engaging said head portion of said open loop.
 7. Thread-braking device as claimed in claim 1 wherein a plurality of axially aligned reversing thread guides is secured to said braking surface of said brake means; wherein said first guide means include a plurality of guides for supplying a plurality of threads which are respectively doubled-up on said brake surface by said reversing thread guides; wherein said second guide means guide said threads away from said peripheral brake surface, and are adapted to guide the threads to the needles of a textile machine; comprising program control means for said machine; and wherein said program control means operate said adjusting means in accordance with the operations of said needles.
 8. Thread-braking device as claimed in claim 1 including means for manually operating said adjusting means.
 9. Thread-braking device as claimed in claim 1 wherein said first guide means include a guide eye for the thread, and a brake surface adjacent said guide eye for frictionally engaging said thread.
 10. Thread-braking device as claimed in claim 1 wherein said brake means includes a brake member, and a cover surrounding said brake member, said cover being made of plush fabric and forming said peripheral brake surface. 